Python for Data Science - Concatenating and transforming data

2021-06-11 16:02

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Chapter 2 - Data Preparation Basics

Segment 4 - Concatenating and transforming data

import numpy as np
import pandas as pd

from pandas import Series, DataFrame
DF_obj = pd.DataFrame(np.arange(36).reshape(6,6))
DF_obj
0 1 2 3 4 5
0 0 1 2 3 4 5
1 6 7 8 9 10 11
2 12 13 14 15 16 17
3 18 19 20 21 22 23
4 24 25 26 27 28 29
5 30 31 32 33 34 35
DF_obj_2 = pd.DataFrame(np.arange(15).reshape(5,3))
DF_obj_2
0 1 2
0 0 1 2
1 3 4 5
2 6 7 8
3 9 10 11
4 12 13 14

Concatenating data

pd.concat([DF_obj,DF_obj_2],axis=1)
0 1 2 3 4 5 0 1 2
0 0 1 2 3 4 5 0.0 1.0 2.0
1 6 7 8 9 10 11 3.0 4.0 5.0
2 12 13 14 15 16 17 6.0 7.0 8.0
3 18 19 20 21 22 23 9.0 10.0 11.0
4 24 25 26 27 28 29 12.0 13.0 14.0
5 30 31 32 33 34 35 NaN NaN NaN
pd.concat([DF_obj,DF_obj_2])
0 1 2 3 4 5
0 0 1 2 3.0 4.0 5.0
1 6 7 8 9.0 10.0 11.0
2 12 13 14 15.0 16.0 17.0
3 18 19 20 21.0 22.0 23.0
4 24 25 26 27.0 28.0 29.0
5 30 31 32 33.0 34.0 35.0
0 0 1 2 NaN NaN NaN
1 3 4 5 NaN NaN NaN
2 6 7 8 NaN NaN NaN
3 9 10 11 NaN NaN NaN
4 12 13 14 NaN NaN NaN

Transforming data

Dropping data

DF_obj.drop([0,2])
0 1 2 3 4 5
1 6 7 8 9 10 11
3 18 19 20 21 22 23
4 24 25 26 27 28 29
5 30 31 32 33 34 35
DF_obj.drop([0,2],axis=1)
1 3 4 5
0 1 3 4 5
1 7 9 10 11
2 13 15 16 17
3 19 21 22 23
4 25 27 28 29
5 31 33 34 35

Adding data

series_obj = Series(np.arange(6))
series_obj.name = "added_variable"
series_obj
0    0
1    1
2    2
3    3
4    4
5    5
Name: added_variable, dtype: int64
variable_added = DataFrame.join(DF_obj,series_obj)
variable_added
0 1 2 3 4 5 added_variable
0 0 1 2 3 4 5 0
1 6 7 8 9 10 11 1
2 12 13 14 15 16 17 2
3 18 19 20 21 22 23 3
4 24 25 26 27 28 29 4
5 30 31 32 33 34 35 5
added_datatable = variable_added.append(variable_added, ignore_index=False)
added_datatable
0 1 2 3 4 5 added_variable
0 0 1 2 3 4 5 0
1 6 7 8 9 10 11 1
2 12 13 14 15 16 17 2
3 18 19 20 21 22 23 3
4 24 25 26 27 28 29 4
5 30 31 32 33 34 35 5
0 0 1 2 3 4 5 0
1 6 7 8 9 10 11 1
2 12 13 14 15 16 17 2
3 18 19 20 21 22 23 3
4 24 25 26 27 28 29 4
5 30 31 32 33 34 35 5
added_datatable = variable_added.append(variable_added, ignore_index=True)
added_datatable
0 1 2 3 4 5 added_variable
0 0 1 2 3 4 5 0
1 6 7 8 9 10 11 1
2 12 13 14 15 16 17 2
3 18 19 20 21 22 23 3
4 24 25 26 27 28 29 4
5 30 31 32 33 34 35 5
6 0 1 2 3 4 5 0
7 6 7 8 9 10 11 1
8 12 13 14 15 16 17 2
9 18 19 20 21 22 23 3
10 24 25 26 27 28 29 4
11 30 31 32 33 34 35 5

Sorting data

DF_sorted = DF_obj.sort_values(by=(5),ascending=[False])
DF_sorted
0 1 2 3 4 5
5 30 31 32 33 34 35
4 24 25 26 27 28 29
3 18 19 20 21 22 23
2 12 13 14 15 16 17
1 6 7 8 9 10 11
0 0 1 2 3 4 5

Python for Data Science - Concatenating and transforming data

标签:dde   ati   taf   apt   imp   pre   ica   from   datatable   

原文地址:https://www.cnblogs.com/keepmoving1113/p/14223109.html


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